Reaction arm



FIG. 1 is a perspective view of a reaction arm showing my new design;

FIG. 2 is a side view thereof which is a mirror image of the opposite side thereof;

FIG. 3 is an end view thereof;

FIG. 4 is the opposite end view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a top view thereof. 

The ornamental design of a reaction arm, as shown and described. 